We present the concept and the application of the molecular jet (MoJet) printing technique. Using this technique, we demonstrate patterned molecular organic semiconducting thin films directly printed by local evaporative deposition. Three stages are involved in the printing process. In the first stage, HP thermal InkJet printing technology is used to deliver ink drops to a micromachined silicon membrane consisting of an array of micrometersize pores and an integrated heater. Once the ink is filled inside the pores, in the second stage a small current is passed through the heater to completely drive off solvent from the micro-pores. In the final stage, pulsed current of larger magnitude is applied to heat up the pores to a temperature sufficient to discharge the dry ink materials out of the pores and form molecular flux. The flux is then deposited onto a nearby substrate to form designated thin film patterns.The MoJet printing technique can be applied to pattern solution-processable molecular organic thin films, providing fluxon-demand in an ambient environment.